1. Technical Field
The present invention relates to a phosphor suitable for vacuum ultraviolet ray-excited light-emitting elements such as a plasma display panel (hereinafter referred to as “PDP”) and a rare gas lamp, and a vacuum ultraviolet ray-excited light-emitting element in which said phosphor is used.
2. Description of Related Art
Phosphors are used in vacuum ultraviolet ray-excited light-emitting elements such as plasma display panels and rare gas lamps, and phosphors which emit lights under excitation with vacuum ultraviolet rays have already been known. Of these phosphors, as aluminate phosphors, there have been put to practical use BaMgAl10O17:Eu as a blue-emitting phosphor and BaAl12O19:Mn as a green-emitting phosphor. Furthermore, as aluminate phosphors used for vacuum ultraviolet ray-excited light-emitting elements, there have been proposed Ba0.83Al11.9Mn0.05O18.73 (see, e.g., JP-A-10-1666) or CeMgAl11O19:Tb (see, e.g., “Phosphor Handbook” compiled by Phosphor Research Society, p. 332, published by Ohmsha, Ltd. on Dec. 25, 1987) as a green-emitting phosphor, and Ba0.9Eu0.1MgAl10O17 (see, e.g., JP-A-8-115673) as a blue-emitting phosphor.
Here, vacuum ultraviolet ray-excited light-emitting elements generate plasma by discharging in a rare gas, and phosphors arranged in the vicinity of the places where plasma is generated are irradiated with vacuum ultraviolet rays radiated from the plasma to excite the phosphors, thereby to emit visible lights radiated from the phosphors. The phosphors are exposed to plasma. Conventional phosphors have the problem that luminance of the phosphors decreases after exposure to plasma, and there have been demanded to develop phosphors less in decrease of luminance after exposure to plasma.